I've seen a few 1.4x Canon tele (series 1) units on e-bay and am wondering if they are any better than the Kenko 1.4 pro or is the Canon 1.4 II Better? I cannot afford the series 3. I'm using the 60D with a 70-200 f4L IS.

So, I real question is: Canon 1.4 tele series 1 or Series II, or the Kenko Pro 300 DGX?

the kenko teleplus DGX 1.4 is about equal quality to the canon mk3 tele convertersno weather sealing though. the benefit of the kenko is it will work on any EF lensI used to love using it on my 28-300 with a 1D since it could AF at f8 it was super handyalso really good on the 100 f2.8L macroMy 5Dmk3 threw a fit when i tried to use the kenko on it but when I emailed kenko they said they had no problems on their test cameraI have now returned that body and waiting for a replacement the kenko stuff still works perfectly on my 5Dmk2s and 1D mk3

I also have the kenko AF chip extension tube set which is also great value and give full exif data and retain AF

I have had the canon 1.4 version II for a year or so and found that (at least on my 100-400) the reduction in sharpness was significant. I was using it with the leads taped so I was able to get autofocus on my 5dII but it would hunt for focus in low light as expected. On the 7D it would almost never focus.

I picked up the Kenko DGX 300 1.4 teleconverter a few weeks ago and have found the sharpness to be excellent and autofocus works quite well on my 100-400 with the 5dII. Again the 7d is not able to focus as quickly or as often with this combination but it does work.

So far I'm very impressed with the quality of the Kenko for the cost. I have not had any opportunity to compare it to the canon 1.4 vIII or with the sigma 1.4 but it was certainly a good investment for what I am shooting right now.

I have now returned that body and waiting for a replacement the kenko stuff still works perfectly on my 5Dmk2s and 1D mk3

I'd be interested to know if your new 5D MkIII body works with Kenko 1.4x DGX. I kind of doubt it since my own 5D MkIII does not work with Kenko 1.4x DGX. Actually, ONLY the Canon 70-200 f/2.8 MkII works now..

yeah me too I have been in email contact with kenko over this and they say they dont have a problemsomeone else here reported their extension tube worked fine. It seems pretty hit and miss at the moment

The Canon 1.4X and 1.4X II are identical except for added weather sealing. The Kenko is pretty much equivalent. I was thinking of getting Kenko until I read of the compatibility issues with the 5D MK III that some posting here have had.

Now that the 1 series no longer supports f/8, and my 5D MK III does not focus well with most f/8 lens/TC combinations after I tape the pins, I may just sell my TC's. There is little advantage to using them with my 70-200mm f/8, since I have a 100-400mm L already.